Piston and rod-packing ring



Jan. 21, 1941. s BUNN PISTON AND ROD-PACKING RING Filed June 16, 1937awn,

all I juvenioz': Edwardilf v- I'WCHZi/i Patented Jan. 21, 1941 UNITEDSTATES PATENT OFFICE PISTON AND ROD-PACKING RING Application June 16,1937, Serial No. 148,562

8 Claims.

My invention relates to piston and rod-packing rings formed ofcopper-base alloys containing ingredients for improving the durabilityand properties of the rings and for facilitating their fabrication.

The invention will be best understood from the following description ofseveral examples of the rings, the scope of which invention will be moreparticularly pointed out in the appended claims.

m It is common practice to make piston and rodpacking rings,particularly those of large diameter, by turning and cutting the same,in a lathe or boring mill, from elongated cast sleeves. It has also beenproposed to extrude, or, as it is sometimes called, fdie-express rodshaving the cross-section desired in the ring element and bend lengths ofthe rods to form these elements either as segments for a segmental ringor as rings of complete, or substantially complete, circumference.Heretofore piston and rod-packing rings machined from castings as aboveexplained have presented many serious defects, particularly that in usethey are subject to cracking and breakage, and crumbling away of sharpcorners and portions thereof of reduced cross-section such as flanges.Many copper-base alloys suitable for extrusion do not when extruded formsatisfactory piston rings.

Applicant has found that by forming the rings of brass into which isincorporated nickel the above mentioned'defects of prior rings areeliminated, and at the same time is further presented an alloy admirablysuited for extrusion purposes thus enabling the .rings to beinexpensively formed by the extrusion and bending process abovementioned. Rods of such alloy further are capable of being hot rolledand forged, enabling rods to be made by either extrusion or hot rollingand the rings to be forged from them.

In addition the metal has the property of permitting a slight colddrawing or other cold working to harden or strengthen the ring.

Rings according to applicant's invention are not limited to those of anyparticular crosssectional shape or other details of construction. Thering elements for example may be formed 4 as segments or as completecircumferences as shown in the accompanying drawing in which Figure 1 isa plan of one form of ring, Figure 2 is a section on the line 2-2 ofFigure 1, Figure 3 is a plan of another form of ring, and Figure 4 is asection on the line 44 of Figure 3. The ring according to Figures 1 and2 is formed of segments I made according to applicant's invention, theouter surfaces 2 of which segments are held against the cylinder wall bya split steel ring 3. The ring element 4 according to Figures 3 and 4,instead of being segmental and of complex cross-section, is in theformof a split ring of complete circumference and is of rectangularcross-section. 5

Excellent results may be secured with a brass having, approximately, 54to 75% copper and with 0.25 to 5% nickel substituted for an equal amountof the zinc. Rings formed of such an alloy in addition to the propertiesmentioned above have excellent resistance to abrasion, toughness, highstrength, good wearing proper-' ties, and reasonably good corrosionresistant properties, and may be machined. These additionalpropertiesare imparted largely by the nickel, and. as a result of themthe above mentioned defects of prior rings are effectively eliminated.

Preferably the amount of nickel does not exceed approximately 2.5% asits maximum effects are secured at that percentage, and the addition ofmore nickel does not materially improve the alloy except making itharder and tougher at the expense of its workability. In practice, 25amounts of nickel in excess of 4 or 5% are generally undesirable.

Preferably, in addition to nickel, the alloy of which the ringelementsare formed also contains iron, which latter may be substitutedfor an equal amount of the zinc. The iron, particularly in conjunctionwith the nickel, materially increases the hardness and toughness of thering and its resistance to abrasion and. wear. Preferably the amount ofiron should not exceed about 2% because this is the maximum amount whichis soluble in the alloy, and any excess amount would be present as freemetallic iron which would make the ring subject to fatigue failure. Inpractice, appreciable results are secured with about 0.25% iron, and tokeep to a 40 minimum the amount of free iron present the alloypreferably should contain no more than about 3% iron.

Arsenic also preferably is added to the alloy as it is found that, amongother things, it increases the toughness of the ring and reduces itstendency to crack and crumble away. It-secures this increase intoughness without detracting from the facility with which the alloy maybe worked, and thus when present does not reduce the ease with which thering m be fabricated. 'It has also been found that arsenic in a brasspiston ring acts to prevent deterioration of the ring by inhibiting thetend- 55 ency of the zinc to volatilize when the ring is subjected tohigh temperatures during use. This volatilization of, zinc othewisewould render the rings unsuitable for use in many situations. Preferablythe amount of arsenic should not exceed 1%, and appreciable results willbe secured with an amount as low as 0.05%.

In respect to the copper and nickel, and also iron and arsenic if eitheror both of these last two are present with the copper and nickel, thebalance of the alloy, neglecting impurities, is substantially zinc inthe sense that such balance is all zinc or all zinc except for smallamounts of elements added for imparting special properties to the alloywithout eliminating its characteristic properties, or added for insuringthe existence of or for modifying those characteristic properties. Itwill therefore be understood that in the appended claims by the words"balance substantially zinc is meant that the balance is zinc in thesense defined. Among such other elements is manganese, small amounts ofwhich may be added to the melt to insure against the deleterious effectsof sulphur that may be present in the alloy. The sulphur if present willunite with the manganese to form manganese-sulphide which in smallamounts has little or no effect on the properties of the alloy, but inthe absence of manganese the sulphur will unite with the nickel to formnickel-sulphide which, even in small amounts, it has been found has adeleterious effect on those properties of the alloy which enable therings readily to be fabricated therefrom. Preferably the manganeseshould not exceed 1% of the final alloy, and ordinarily it should bepresent in amounts exceeding 0.05%. Another of such additional elementsis lead, which may be added in small amounts to facilitate the ease withwhich the ring element may be machined and to improve its properties asa bearing. Lead from 0.1 to 1% will. have appreciable effects in respectto improving the bearing properties and may be added up to 2.5% forimproving the machining properties, without particularly modifying anyof the characteristic properties of the alloy, except, for the reasonthat it constitutes a soft material entered into an otherwise hard alloyand being dispersed but not dissolved in that alloy, it acts to improveits machining, wearing and bearing properties. Still another of suchelements which may be added is silicon, although ordinarily that elementwill not be needed. Silicon acts as a deoxidizer in the melt and alsoacts somewhat to increase the tensile strength of the ring, and itsresistance to corrosion when subjected to oil and steam at hightemperatures. As little as. 0.25% silicon will give appreciable results.Preferably, however, the silicon should not exceed 1%, so as notmaterially to decrease the ease with which the rings may be fabricated.

.[t will be understood from the foregoing that the preferred alloy foran extruded ring contains between 54 and 64% copper, 0.1 and 2.5%nickel,

0.10 and 2% iron, 0.05 and 1% arsenic, 0.05 and 1% manganese, and'0.2and 1% lead, with the balance zinc. Thealloys containing the lesseramounts ofcopper and the greater amounts of other constituents withinthe ranges mentioned have the. best hot working properties in respect tofabricating the ring, and require a minimum of cold working to developmaximums of strength in the ring, whereas the alloys having the greateramounts of copper and the lesser amounts of the other constituents arenot so easily hot worked to form the ring. Nevertheless the alloyscontaining the greater amounts of copper have sufflcierit plasticitywhen heated to a temperature range of 1200 to 1500 1?. to enable themreadily to be formed into rings, or rods from which rings may be formed,by hot rolling or hot forging, and further may be hot extruded to formthe rods of which the rings are made, but not with the same ease as thealloys containing the lesser amounts of copper.

It will be understood that within the scope of the appended claims widedeviations may be made from the rings above described without departingfrom the spirit of the invention.

I claim:

1. A piston or pacln'ng ring element of an alloy which basically is abrass containing nickel, the amount of copper being approximately 54 to75% of the alloy, the amount of nickel approximately 0.25 to thereof,and the amount of zinc being not less than about 11.5% or more thanabout 46% thereof.

2. The ring element according to claim 1 containing, approximately, 0.05to 1% arsenic.

3. The ring element according to claim I having, approximately, notmorethan 69% copper and not more than 4% nickel, and containing,approximately, 0.25 to 3% iron.

' 4. The ring element according to claim 1 having, approximately. notmore than 69% copper and not more than 4% nickel, and containing,approximately, 0.25 to 3% iron and 0.05 to 1% arsenic.

5. An extruded metal piston or rod packing ring element consisting of analloy which basically is a brass containing nickel, the amount of copperbeing approximately 54 to 75% of the alloy, the amount of nickelapproximately 0.25 to 5% thereof, and the amount of zinc being not lessthan about 11.5% or more than about 46% thereof.

6. The ring element according to claim 5 containing, approximately, 0.05to 1% arsenic.

7. The ring element according to claim 5 having, approximately, not morethan 69% copper and not more than 4% nickel, and containing,approximately, 0.25 to 3% iron.

8. The ring element according to claim 5 having, approximately, not morethan 69% copper and not more than 4% nickel, and containing,approximately, 0.25 to 3% iron and 0.05 to 1 arsenic.

EDWARD S. BUNN.

